1. Technical Field
The invention relates to a process for increasing the stability of a vehicle upon acceleration on a roadway with a non-homogenous coefficient of friction, whereby a drive wheel is acted on with a braking force on the side with low coefficient of friction by means of acceleration slip regulation.
The invention additionally relates to an apparatus suitable for the implementation of the process.
2. Description of the Related Art
Upon the acceleration of a vehicle, an excess rotation of the drive wheels can occur, particularly on a roadway with a low coefficient of friction, through which the lateral guiding force that can be transmitted by the tires is reduced. The result is a destabilization of the vehicle, which can, in vehicles with rear drive, for example, lead to an oversteering when rounding a curve.
Modern vehicles thus have regulating systems that reduce the slipping of the wheels on excessively rotating drive wheels through engagement of the brakes to the value that is necessary to guarantee traction, so that a greater drive torque is imparted to the wheels, and the lateral guiding force that can be transmitted by the tires is increased. These regulating systems are termed acceleration slip regulation (ASR). In addition, the terms “electronic differential lock (EDS),” “automatic stability control (ASC),” and “traction control system (TCS)” are commonly used.
In a μ-split situation—that is to say, upon the presence of a non-homogenous coefficient of friction of the roadway—the drive wheel is, during an ASR engagement, braked on the side with a low coefficient of friction. Because of the effect of the compensation gear (differential) of the drive axle, the drive force is increased on the side with a high coefficient of friction relative to the drive force on the side with a low coefficient of friction, and a disrupting yaw momentum arises on the vehicle. This can lead to a veering or to an inward turning of the vehicle into the direction of the side with a low coefficient of friction, as the case may be, if a sufficient lateral guiding force for supporting the lateral force brought about by the disrupting yaw momentum cannot be built up on the tires.